Influence of the fibre laser parameters on the surface texturing of 420 stainless steel

The surface of an annealed 420 stainless steel plate was textured using a fibre laser in this work. Four hundred textures were produced from eighty different combinations of processing parameters (laser power, scan speed, line spacing and number of passes). The most promising textures (fourteen combinations of the processing parameters) were obtained with laser power values of 16 and 64 %, scanning speeds up to 2,000 mm/s, number of passes of 8 or higher and line spacings of 40 and 50 µm. The lower the laser power, the lower the scanning speed and the high number of passes and line spacings were required for a suitable ablation process. High laser powers were responsible for the dissolution of the chromium carbides in the laser tracks (top and edges of the unmachined areas). The hardness of these regions was 320 ± 11 HV against 255 ± 5 HV for the unmachined zones.